I believe GIMP# has that as a goal, but it was not even ready for beta last time I checked a few months ago.
To be honest, after a few weeks, this just passed and seemed normal to me. One thing, if you are going to be using the same tool for quite a while, you can just maximize the "picture" window. Then, you can press a key to bring the other windows back on top. I think it's F12, but can't look it up right this sec.